1. Field of the Invention
The present invention pertains generally to the field of body supporting and cushioning devices and more particularly relates to seat cushions and body supports directed to meet the needs of persons who are chair-bound for medical or other reasons over protracted periods of time, and diagnostic devices for properly fitting such cushions to the needs of particular individuals.
2. State of the Prior Art
Much inventive activity has been directed to the development of various cushioning and support devices for use by the handicapped, the chair-bound, the bed-ridden, and generally by non-ambulatory individuals. A recurrent problem encountered by such persons is the increased likelihood of ulceration and damage to skin and underlying tissues at areas of the body which are subjected to continuous moderate or high levels of pressure over periods of hours and sometimes days without relief. Such conditions lead to the formation of decubitus ulcers, commonly known as bed sores.
Protracted pressure against any portion of the skin has the effect of diminishing- or cutting off peripheral vascular flow to that area. If impairment of blood flow to the affected area is sufficiently prolonged, the tissues underlying the affected skin area will be starved of nutrients and suffer progressive damage. Typically it is the underlying soft tissues which are first damaged, until eventually the skin undergoes necrosis and ulcerates in progressive manner, and unless the pressure on the area is removed, such ulcers can become deep open wounds which are difficult to treat and slow to heal.
Even moderate levels of pressure over relatively brief periods of time can lead to significant skin and tissue damage and much effort has therefore been expended towards providing improved seat cushions and back-pads for non-ambulatory persons confined to wheel chairs. The difficulties encountered by such persons are frequently compounded by medical conditions which may insensitize the person to progressive skin and tissue damage until such damage has reached advanced and serious stages, and by conditions which deprive the individual of any ability to reposition him or herself so as to relieve continuous pressure on any particular portion of the anatomy to thus stem the formation of ulcerations or other soft tissue damage by periodically shifting position.
One anatomical area which is particularly susceptible to soft tissue damage in persons confined to a sitting position over protracted periods of time is the skin and soft tissue overlying and adjacent to the ischial tuberosities of the pelvis, and the sacral and coccyx areas, particularly in the case of those with spinal cord injury. In such cases, utmost care must be taken to minimize pressure levels on certain portions of the anatomy which are particularly susceptible to the formation of decubitus ulcers, and to distribute the pressures exerted by cushions or other body support devices in a manner which reduces peak pressure levels to acceptable levels considered to be relatively benign over longer periods of time.
There is a continuing need for more effective, simpler and easier to fit devices in furtherance of the above mentioned objectives.